82. CONTRIBUTION TO 



NUCLEOCRINUS ANGULARIS, Lyon, Rowley. 



Plate 27. Fig. 1, 2, 3-4. 



The radial plates of this blastoid are short, the interradials occupying 

 more than nine-tenths of the body length. The basals are three in number 

 and rather small, extending but little beyond the upper stem joint. 



The column is round, medium in size and A\ith a small, round canal. The 

 base is flat or but slightly concave. The interradial areas have the mid-trian- 

 gular space hardly traceable, except in the anal field, where it is bilobed and 

 with a central sulcus. 



The ambulacra are narrow and with the upturned edges of the bounding 

 interradials form five ridges with interambulacral valleys between. 



The summit is slightly concave and the central opening is covered by a 

 roof of small pieces. 



The spiracles are elliptical, ten in number,, and somewhat roofed over by 

 the edge of the interradials. The anal opening is elongate oval. The anal 

 area is noticeably wider than the other areas. 



The ornamentation is faint, longitudinal lines, apparently nearly parallel 

 with the ambulacra. 



TJie three specimens figured are from the Upper Devonian beds near 

 Charlestown, Ind., and form part of the collection of Mr. G. K. Greene. 



NUCLEOCRINUS V E N U S T U S , M. & G., Rowley. 



Plate 27. Figs. 5. 6, 7-8. 



This little blastoid evidently belongs to the Angularis group. Compared 

 with y^. Angularis, it is smaller, more elongate, less sharply five lobed, the 

 interambulacral areas being less depressed. The mid-interambulacral tri- 

 angles more sharply defined and giving to the ambulacral areas a lobed instead 

 of angular appearance. 



The base is flat or slightly concave. The basals are small and so is the 

 column. 



The plate ornamentation is like that of Angularis. The ambulacra are narrow. 



Spiracles and anal openings as in Angularis. 



The central summit opening is covered by a roof of small plates. 



The anal area is wider than the other interradial areas. 



The radial plates seem to be a little longer in proportion to the interradials 

 than in Angularis. 



